Roundtable lawmaker Michael Tien on Monday criticised the government for increasing its cost estimate for the construction of a new MTR station in the New Territories by almost 70 per cent, saying the cost overruns were "outrageous".

In a paper submitted to the Legislative Council last week, the government revealed that the construction of the new Kwu Tung station would now cost an estimated HK$5.9 billion - HK$2.4 billion more than the 2021 estimate.

Tien, who is a member of Legco's transport panel, said there had been no proper explanation from the government.

“The government explained the 2021 estimation is based on a 2015 or 2016 set of assumptions. And then they went on to explain that the area [of construction] has increased by 20 percent and due to inflation from 2015 until now,” he said.

“I go and take a look at the inflation. The total inflation from 2015 to now is about 16 percent. So I add 20 percent to the $3.5 billion and another 16 percent. I do not at all get anything close to $5.9 billion… I used all the arguments they gave ... and still couldn’t add up to that number.”

But a former president of the Hong Kong Institution of Engineers, Aaron Bok, defended the government's estimate, saying the original estimate was made years ago and that rising costs should be taken into account.

The government also announced last week that a project that involves the construction of a 2.3-kilometre trunk road in Sha Tin is now expected to cost more than HK$7.1 billion, far higher than the original estimate of HK$1.1 billion in 2006.